1. Field of the Invention
The invention relates to a sensing device, and more particularly, to a sensing device with low power noise.
2. Description of the Related Art
Generally, power noise is a problem in COMS image sensors. Especially, when CMOS image sensors operate at low light conditions, the power noise may affect disadvantageously the sensing quality. Several manners have been provided to reduce the effect of the power noise. In one manner, a low pass filter is used to filter out noise from a power line. However, when an on-chip RC filter is used, high-frequency noise is not easily filtered out. Moreover, if an off-chip RC filter is used for a CMOS image sensor instead of on-chip RC filter, the off-chip RC filter will increases the cost of the COMOS image sensor. In another manner, a regulator is used to generate clear power with low noise. However, high-frequency noise is also not easily filtered out. Thus, the power may still contain some high-frequency noise components.